The present invention relates to a set of iron-type golf clubs capable of reducing variation in spin amount at mis-shots for long iron clubs and capable of increasing accuracy in shots intentionally curving a ball for short iron clubs.
In order to increase flight distance of a ball by optimizing a frictional condition of a face, JP 2008-005994 proposes an iron-type golf club head having a face provided with a plurality of face grooves extending in a toe-heel direction and having a depth of 0.200 to 0.508 mm and a plurality of auxiliary grooves having a depth of 0.005 to 0.025 mm.
In order to effectively exhibit the action of the auxiliary grooves, the present inventor made a study about actual use of iron-type golf club heads having different loft angles.
So-called long irons having a small loft angle are generally used for hitting a ball straight with a stance square to a distant target. Therefore, in case of the long irons, shots to intentionally curve a ball greatly or shots to cut across a ball with a clubface opened are not so frequent. Further, such shots by the long irons may be technically difficult, since a club head of the long irons is relatively small. On the other hand, probability of mis-shots by long irons such as hitting on a toe or heel side of a face is relatively high, since the length of the clubs is relatively large.
So-called short irons having a large loft angle are generally used to carry a ball from the periphery of a green, a bunker, a rough and so on to a relatively near target such as a green. Therefore, in order to avoid an obstacle, there are frequently conducted so-called intentional shots wherein a ball is hit in the state that a clubface is opened or closed to intentionally curve the ball. Since a club head of the short irons is relatively large, such a use is technically easy. Further, since the length of the short iron club is relatively small, probability of mis-shots by short irons such as hitting on a toe or heel side of a face is lower than the long irons.
Like this, there are cases where main purpose and status of use are different between long irons and short irons.
It is an object of the present invention to provide a set of iron-type golf clubs wherein long irons are capable of reducing variation in spin amount at mis-shots, thereby stabilizing the flight distance, and short irons are capable of imparting a sufficient spin amount to a ball even at intentional shots for intentionally curving a ball, thereby increasing accuracy of shots by short irons.
This and other objects of the present invention will become apparent from the description hereinafter.